Effects Of w’ Depletion On The Torque Velocity Relationship In Cycling

Abstract

The torque-velocity (T-v) curve has been used to study the effects of energy expenditure on contractile muscles at various workloads related to VO2max. PURPOSE: The purpose of this study was to further quantify changes to the T-v curve, but based on anaerobic energy (W’) expenditure at powers above Critical Power (CP6). METHODS: A group of 10 subjects (37.8 ± 11.6 yrs, 72.8 ± 16.2 kg, 1.75 ± .11 m) performed a Time to Exhaustion Test (TTE) interspersed with 6-second sprints to generate their T-v curve at 3 stages of W’ expenditure: after initial warmup (FRESH), fatigued (after 2 minutes at CP6, 2MIN), and at TTE. RESULTS: ANOVA results indicated a statistically significant decrease in normalized Maximal Power (Pmax) from FRESH to 2MIN (16.89%, p<.0005), 2MIN to TTE (24.71%, p=.004), and from FRESH to TTE (41.6% p=.04). Statistically significant decreases in normalized Maximal Velocity (vo) were seen from FRESH to 2MIN (14.1%, p<.0005), from 2MIN to TTE (11.8%, p=.001), and FRESH to TTE (25.9%, p<.0005). No significant changes occurred in Maximal Torque (To). Linear regression models were run using W’ expended to explain variations in Pmax, vo, and To. There were significant negative correlations for To (P = 0.020) and significant strong negative correlations for Pmax (P < 0.005), and vo (P < 0.005). CONCLUSIONS: This suggests that W’ expenditure can be used to predict the performance parameters Torque (To), Shortening velocity (vo), and Maximal Power (Pmax) during continuous cycling above Critical Power.